U.S. military veterans denounced Donald Trump and delivered petitions Thursday to Capitol Hill, urging Senator John McCain and other Republican elders to withdraw endorsements of their party's presidential nominee.

"Donald Trump's reckless ignorance about America's responsibilities in the world shocks me to the core," said Marine veteran Alexander McCoy. "We have listened as he praised and has been praised by brutal dictators. We have listened as he threatened to abandon our most loyal allies. … I am done listening.

"We cannot afford to have Donald Trump as commander in chief," McCoy added.

"Donald Trump's hate speech, bigotry and unabashed incitement to violence against minorities, to include the Muslim community, desecrate the very values of liberty and equality which we as American military veterans swore an oath to protect," said Muslim Navy veteran Nate Terani. "It should be the solemn duty of lawmakers like Senator John McCain to denounce and unendorse Donald Trump."

FILE - Khizr Khan, whose son Humayun was killed serving in the U.S. Army, challenges Republican presidential nominee Donald Trump to read his copy of the U.S. Constitution at the Democratic National Convention in Philadelphia, July 28, 2016.

Trump has faced a backlash, including from prominent Republicans, for belittling Khizr and Ghazala Khan, the Muslim parents of the U.S. soldier killed in Iraq. Khizr Khan blasted Trump's proposed ban on Muslim immigrants, drawing the candidate's ire.

The episode is the latest in which Trump's words have put Republicans on the defensive, including many lawmakers seeking reelection in November.

McCain, a Vietnam War veteran and the 2008 Republican presidential nominee, sought to distance himself from Trump earlier this week.

"Donald Trump disparaged a fallen soldier's parents. He has suggested that the likes of their son should not be allowed in the United States," McCain wrote in a statement. "I cannot emphasize enough how deeply I disagree with Mr. Trump's statement. I hope Americans understand that the remarks do not represent the views of our Republican Party."

But McCain, while campaigning fiercely to retain his Senate seat in a state Trump carried in the primaries, has not rescinded his endorsement of the nominee, nor given any indication he plans to do so.

FILE - A veteran watches as U.S. Republican presidential nominee Donald Trump speaks to the Veterans of Foreign Wars conference at a campaign event in Charlotte, North Carolina, July 26, 2016.

Meanwhile, a few prominent Republicans have offered tepid defenses of Trump's comments about the Khan family.

Neurosurgeon Ben Carson, who competed in the Republican presidential primaries, has said the Khans and Trump should apologize to each other.

Trump initially took to Twitter to complain that Khan does not know him but "viciously attacked" him at the Democratic National Convention and in subsequent television interviews.